This invention relates to fused pyrazole compounds which are novel and useful as pharmaceuticals.
Heretofore, as fused pyrazole compounds, there have been described the indazole derivatives in Japanese Patent Application Laid-open (Kokai) No. 125281/1976 and pyrazolo[3,4-b]pyridine derivatives in U.S. Pat. No. 3,983,128 respectively.
Meanwhile, with the considerable developments of chemotherapeutic agents in the recent years, there has been seen remarkable progress in the therapy of infectious diseases. On the other hand, however, there have appeared new problems such as opportunistic infectious diseases on which the previous chemotherapeutic agents fail to effectively act and infectious diseases which result from leukopenia caused by the application of radiation-therapy or medicine-therapy to patients of cancers. For the purpose of the treatment of such infectious diseases, there have been desired not only the application of antibacterial agents but also the development of the medicines which are capable of recovering infection-phylactic action of feeble patients. However, success has not been attained.